Mesh bend as it follow curve along path
The Tilt of the vertices are at 0° (3D View &gt; N panel) so it's not the problem. You need to select the curve and choose Twist Method &gt; Z-Up. That said the object is still not completely vertical. If it's too noticeable you need to switch to the Instancing method: Give the Array and Curve modifier to a vertex instead of your object, enable the Instancing &gt; Vertex of this vertex, and parent your object to the vertex.